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Smallest k > 1 such that k | Sigma(k) + n.
1

%I #8 Oct 01 2018 06:57:06

%S 6,2,3,2,5,2,6,2,3,2,11,2,6,2,3,2,17,2,6,2,3,2,10,2,5,2,3,2,28,2,6,2,

%T 3,2,5,2,6,2,3,2,41,2,6,2,3,2,14,2,6,2,3,2,10,2,5,2,3,2,20,2,6,2,3,2,

%U 5,2,6,2,3,2,40,2,6,2,3,2,7,2,6,2,3,2,10,2,5,2,3,2,14,2,6,2,3,2,5,2,6,2,3

%N Smallest k > 1 such that k | Sigma(k) + n.

%H Antti Karttunen, <a href="/A055942/b055942.txt">Table of n, a(n) for n = 0..65537</a>

%t Do[ k = 2; While[ Mod[ DivisorSigma[ 1, k ] + n, k ] != 0, k++ ]; Print[ k ], {n, 0, 100} ]

%o (PARI) A055942(n) = for(k=2,oo,if(!((sigma(k)+n)%k),return(k))); \\ _Antti Karttunen_, Sep 30 2018

%Y Cf. A000203.

%K easy,nonn

%O 0,1

%A _Robert G. Wilson v_, Jul 18 2000